Apparatus for maintaining a supply of air at low pressure



Aug. 11,1925. 1,549,378

E. B. PERRINE APPARATUS FOR MAINTAINING A SUPPLY OF AIR AT} LOW PRESSURE Filed Nov. 8, 1920 ll ll In "Z I vvE/VTOR 5 6: 5VIMETT 5. PE RI'NE.

EYW M Patented Aug. ll, 1925.

UNITED EMMETT B. PERRINIE. 01i MINNEA?OLIS, MINNESOTA.

APPARATUS FOR MAINTAINING SUPPLY OF AIR AT LOW PRESSURE.

Application filed November 8, 1320. Serial No. 422,694.

T 0 all whom it may concern:

Be it known that I, EMMETT B. PERRINE, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Apparatus for Maintaining a Supply of Air at Low Pressure, of which the following is a specification.

My invent-ion relates to apparatus for maintaining'a supply of air at low pressure. An object of the invention is to provide apparatus which-will automatically maintain a supply of low pressure air by means of a supply of high pressure air without the use of a pressure reducing valve. An object in particular is to provide apparatus in which a motor is operated by high pressure air to drive a pump which furnishes a supply of low pressure air. Another object is to provide for conducting the air used to drive the motor into the supply of low pressure air furnished by the pump.

The full objects and advantages of invention will appear in connection with the detailed description thereof, and the novel features embodied in my inventive idea will be particularly pointed out in the claims.

In the accompanying drawings which illustrate one embodiment of my invention, Fig. 1 is a sectional elevational view of the apparatus. Fig. 2 is a view in cross section substantially on the line 22 of Fig. 1. Fig. 3 is a fragmentary view in longitudinal section showing a controlling valve.

Referring to the particular construction shown in the drawings, the numeral 10 designates a storage tank for holding air at a comparatively low pressure, and this air is intended to be delivered through a pipe. 12 for various purposes, such as operating a pneumatic cash carrier system. A pipe 14 leads from a suitable supply of high pressure air into a casing 16 which is divided by a partition 17 into a large compartment 18 and a small compartment- 20. A pair of shafts 22 and 24 extend longitudinally through these compartments. and through the partition17. Outside of the casing these shafts are provided with meshing gears such as 2-6 which cause the shafts to rotate in unison. Secured to the shafts within the compartment 20 are blades 28 and 30, and secured to the shafts within the compartment 18 are blades, one of which is designated by the character 32 and which are preferably similar to, although longer than the blades in the compartment 20. The blades 28 and 30 serve as a motor and are operated by high 14. The blades 28 and 30 drive the blades which are in the compartment 18 whereby these latter blades serve as a pump to draw air in through an aperture 34. in the casing,

and deliver thlS air through the pipe 36 to T the storage tank 10. The aperture 34 may be provided with any suitable form of check valve. The air which has operated the motor in the compartment '20 passes through an aperture 38 in'the partition 17 and is conducted by the pipe 36 to the tank 10. The pressure of air inthis tank is maintained substantially constant and the speed of the pump is prevented from becoming excessive by the following mechanism. A suitabl valve 40 is mounted in the high pressure pipe 14, and an arm 42 attached to this valve is connected by a link 44 to an arm 46 of a lever pivoted at 48 to a support 50. The other arm 52 of the lever is swivelly attached to the lower end of a rod 54, the upper end of which is attached to a conventional form of ball governor 56 which is rotatably supported at its upper end by a bracket 58. The rod 54 extends loosely through a support 60 extending out from the casing 16. Rotatably mounted upon the support 60 is a bevel gear 62 having a key which slidablv fits keyway 64 in the rod 54. Meshing with the bevel gear 62 is a bevel gear 66secured to the shaft 22. Connected to the pipe 36 is a pipe 68 which leads into a casing 70 carried by the support 50. Within said casing is a diaphragm 72 which is connected by a rod 7 4 to the lever arm 46.

The operation and advantages of my invention will be readily understood from the foregoing description. High pressure air is delivered by the pipe 14 from a suitable source to drive the motor in the compartment 20 and operate the pump in the compartment 18 which is adapted to pump a large quantity of air at low pressure into the storage tank 10. When the motor and pump attain a maximum allowable speed, the governor 56 causes the rod 54 to be lifted and depress the lever arm 46 which moves the valve 40 into its partly closed po sition, as indicated, for instance, by the dotted lines in Fig. 3 and thus out down the amount of high pressure air which passes through the pipe. When the air in the storpressure air which comes through the pipe age tank reaches its maximum allowable pressure, the pressure on the diaphragm 72 causes the lever arm 46 to be depressed and this closes the valvel to cut off the supply of high pressure air. YVhen the pressure in the tank'lO falls, the valve again opens and theapparatus is automatically set into operation. In this manner, the air in the storage tank is automatically kept at a substan tially uniform low pressure by means of a limited amount of air at high pressure without the use of a reducing valve. It is to be noted in particularthat the small quantity of high pressure air employed to drive the pump is not wasted but passes into the storage tank through the pipe 36, together with the/air which is forced in by the pump.

I claim: i

1. Apparatus of the character described comprising a motor, means for delivering high pressure air to said motor for driving the same, a pump driven from said motor, a storage tank, means connected with said pump and storage tank whereby air is taken from the atmosphere by said pump and delivered to said tank, means to maintaining the air in said tank at a substantially uniform low pressure, and means for causing the small quantity of high pressure air employed in driving said motor to be deliv ered to said storage tank. p a a 2. Apparatus of the character described comprising a chamber, a rotary motor in said chamber, a second chamber, a rotary pump in said second chamber driven from said motor, means for delivering high pressure air to said first chamber for driving said motor, a passageway between said chambers whereby the small quantity of high pressure air employed in driving said motor will pass into the pump chamber, a storage tank, means connected with said pump and storage tank whereby air is taken from the atmosphere by said pump and dc livered together with the'small quantity of high pressure air to said storage tank, and means for maintaining the air in said. tank at a substantially uniform low pressure.

8. Apparatus of the character described comprising a casing, a partition dividing said easing into a larger and asmaller compartment, a motor in said smaller compartment, a pump in said larger compartment driven by said motor, a pipe for delivering high pressure air to said motor for driving thesame, a storage tank, a pipe for conducting lowpress ure air from said pump to said tank, and for also conducting the air used for driving said motor to said tank, a valve in said high pressure pipe, a governor associated with said motor, a lever connected withsaid governor, connections between said lever and said valve for opening and closing the latter, a casing connected to the supply of low pressure air, a diaphragm in said casing, and connections between said diaphragm and said lever.

In testimony whereof I hereunto aflix my signature.

EMMETl PERRINE. 

